1. Field of the Invention
The present invention relates to a method for producing a rigid magnetic circuit component for an electromagnetically operable value.
2. Description of Related Art
FIG. 1 shows a known fuel injector from the related art, which has a classical three-part construction of an inner metallic flow guidance part and a housing component at the same time. This inner valve pipe is formed by an intake nipple forming an inner pole, a nonmetallic intermediate part and a valve-seat support accommodating a valve seat, and is described in more detail in the associated description of FIG. 1.
A method is known from published German patent document DE 35 02 287 for producing a hollow cylindrical metallic housing having two magnetizable housing parts and a magnetic housing zone lying between them and separating the housing parts magnetically. This metallic housing is pre-worked, in this context, from a magnetizable blank in one piece, right down to an oversize in the outer diameter, an annular groove being cut into the inner wall of the housing to a width of the desired middle housing zone. With the housing rotating, a nonmagnetizable filler material is filled into the annular groove, while the annular groove region is heated, and the rotation of the housing is kept going until the filler material solidifies. The housing is subsequently over-rotated on the outside up to the end measure of the outer diameter, so that there is no longer any connection between the magnetizable housing parts. A valve housing produced in this manner may be used, for instance, in magnetic valves for antilock systems (ABS) of motor vehicles.
Methods are also known from published German patent document DE 42 37 405 for producing a rigid core for injection valves for internal combustion engines (see FIG. 5 of the cited German patent document). The methods are distinguished in that they provide a one-piece, sleeve-shaped, magnetic martensitic workpiece, directly or via prior conversion processes, which experiences a local heat treatment in a middle section of the magnetic, martensitic workpiece for converting this middle section into a nonmagnetic, austenitic middle section. Alternatively, during the local heat treatment, using a laser, elements forming molten austenite or molten ferrite are added to the location of the heat treatment to form a nonmagnetic, austenitic middle section of the rigid core.